Men who have sex with men (MSM) account for many of the new infections in Lebanon and other parts of MENA, and act as a bridge to transmission in the general population;yet this population remains very much understudied in this region. This is in part because same-sex sexual activity is highly stigmatized and even criminalized, making it hard to engage the population in research. The few existing studies suggest high rates of unprotected anal sex and low rates of HIV testing in MSM, but there is a paucity of data to explain the determinants and social underpinnings of such behavior. Social network analysis has rarely been used to study HIV risk behavior in MSM, and never in MENA, yet the social networks in which MSM are embedded represent the social context by which social support, stigma and discrimination, and information exchange may influence health and risk behaviors. Respondent driven sampling (RDS) has become widely accepted as the best approach for accessing populations that are hidden and stigmatized, and it has been used successfully in studies of MSM elsewhere;however, the one quantitative study of HIV risk behavior among MSM in Lebanon used RDS and struggled to enroll participants because of barriers related to stigma, privacy concerns and inadequate incentives. Formative research is imperative for culturally adapting RDS methodology and related study procedures for successful recruitment and data collection. The proposed study will consist of formative research conducted in two phases. In Phase 1, we will use semi-structured interviews to (1) explore how social relationships, stigma and discrimination, social support, and perceived social norms relate to HIV risk behavior and HIV testing, and (2) elicit feedback on methods to bolster access to and recruitment of MSM. Phase 2 will use findings from Phase 1 to develop recruitment strategies and determine appropriate data collection modalities that will be piloted with a cross-sectional survey and social network assessment using RDS. Identifying effective methods for accessing and recruiting MSM, and collecting preliminary data on social network characteristics and their relationship to HIV risk behavior and HIV testing, will provide the foundation for a subsequent larger evaluation, and ultimately inform a network-based prevention intervention. PUBLIC HEALTH RELEVANCE: This study is important to public health as it will provide critical information about how to best access and engage high-risk, hidden populations such as MSM in research, and preliminary data on determinants of HIV testing and risk behavior among MSM in Lebanon. Study data will inform a subsequent larger evaluation study and risk reduction interventions.